In computer security, a login or logon (also called logging in or on and signing in or on) is generally the process by which individual access to a computer system is controlled by identification of the user using security credentials provided by the user. A user can log in to a system to obtain access to the computer system and can then log out or log off (perform a logout/logoff) when the access is no longer needed. To log out is generally to close off one's access to a computer system after having previously logged in.
Traditionally, computers or electronic devices may be locked or otherwise secured to prevent unauthorized or inadvertent usage. Generally, a user is required to perform some affirmative action (e.g., enter a password, type a key combination, move the mouse, swipe a finger across the screen, etc.) to unlock the computer.